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