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