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