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