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