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