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