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