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