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