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