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