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