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