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)(25,26,30,34)(27,35,37,32)(28,31,38,36)(29,33,39,40)(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)(26,32)(28,33)(29,31)(30,37)(34,35)(36,39)(38,40)(9,12)(10,15)(11,17)(13,20)(14,21)(16,24)(18,19)(22,23)(25,28,31,34,30,38,36,26)(27,33,29,35,37,40,39,32)(12,20)(15,24)(17,19)(21,23)(25,29)(26,33)(27,36)(28,35)(30,39)(31,37)(32,38)(34,40) involution — undirected(1,4,5,3)(2,6,7,8)(11,18)(14,22)(17,19)(21,23)(27,37)(29,39)(32,35)(33,40)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.