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