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