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