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