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