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