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)(11,21,24,31,25,30,23,16)(12,17,28,32,26,33,27,34)(22,35,38,39,36,40,37,29)(1,2)(3,4)(6,8)(9,11,13,23,15,25,14,24)(10,16,19,21,20,31,18,30)(12,22,27,37,26,36,28,38)(17,29,32,35,33,39,34,40)(2,4)(6,8)(9,12)(10,17)(11,22)(13,27)(14,28)(15,26)(16,29)(18,34)(19,32)(20,33)(21,35)(23,37)(24,38)(25,36)(30,40)(31,39) involution — undirected(6,8)(10,18,20,19)(12,26)(16,30,31,21)(17,32,33,34)(22,36)(27,28)(29,35,39,40)(37,38)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.