One vertex per element, one color per generator, with an edge from x to x·s.
(1,2,4,6)(3,5,7,8)(9,10,14,18)(11,15,21,16)(12,17,23,13)(19,20,22,24)(25,26,30,29)(27,33,35,31)(28,36,37,32)(34,38,40,39)(1,3,4,7)(2,5,6,8)(9,11,14,21)(10,15,18,16)(12,22,23,19)(13,20,17,24)(25,27,30,35)(26,31,29,33)(28,34,37,40)(32,38,36,39)(1,2)(3,5)(4,6)(7,8)(9,11)(10,16)(12,19)(13,20)(14,21)(15,18)(17,24)(22,23)(25,26,30,29)(27,31,35,33)(28,32,37,36)(34,38,40,39)(1,3)(2,5)(4,7)(6,8)(9,11)(10,15)(12,19)(13,24)(14,21)(16,18)(17,20)(22,23)(25,28)(26,32)(27,34)(29,36)(30,37)(31,38)(33,39)(35,40) involution — undirected(1,2)(3,5)(4,6)(7,8)(9,12)(10,17)(11,19)(13,18)(14,23)(15,20)(16,24)(21,22)(25,27)(26,31)(28,34)(29,33)(30,35)(32,38)(36,39)(37,40) involution — undirected(9,13,14,17)(10,12,18,23)(11,20,21,24)(15,22,16,19)(25,29,30,26)(27,33,35,31)(28,32,37,36)(34,38,40,39)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.