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