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