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