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