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