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