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