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