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