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