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