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