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