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