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