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