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