One vertex per element, one color per generator, with an edge from x to x·s.
(9,10,14,15)(11,19,20,16)(12,17,21,23)(13,18,22,24)(25,26)(27,33)(28,32)(29,30)(31,35)(34,40)(36,38)(37,39)(1,2)(3,8)(4,5)(6,7)(10,15)(13,22)(16,19)(17,23)(26,29)(28,36)(31,33)(34,37) involution — undirected(2,7)(3,4)(11,20)(12,21)(16,19)(17,23)(25,27,30,35)(26,31,29,33)(28,37,36,34)(32,40,38,39)(1,3,6,4)(2,8,7,5)(9,11)(10,16)(12,18)(13,17)(14,20)(15,19)(21,24)(22,23)(25,27)(26,31)(28,34)(29,33)(30,35)(32,39)(36,37)(38,40)(1,4,6,3)(2,5,7,8)(9,12)(10,17)(11,18)(13,16)(14,21)(15,23)(19,22)(20,24)(25,28)(26,32)(27,34)(29,38)(30,36)(31,39)(33,40)(35,37)(1,5)(2,3)(4,7)(6,8)(9,13)(10,18)(11,17)(12,16)(14,22)(15,24)(19,21)(20,23)(25,29,30,26)(27,33,35,31)(28,38,36,32)(34,40,37,39)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.