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