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