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