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